### Added
- Logger class
- getLogger(name)
- Module-level logging helpers (`info`, `debug`, `success`, `warning`, `error`, `fatal`)
- Log levels (0-5) and `setLevel` filtering
- New module `dlf4p/utils.py`
- Test script `test/main.py`
- CONTRIBUTING.md

### Changed
- Added type annotations in logger API
- Exported `Logger` from `dlf4p/__init__.py`
- Fixed internal imports to use package-relative paths
- Update README.md